In an image forming apparatus such as a laser printer, image data is formed as a toner image on a sheet. The toner image is fixed to the sheet by a fixing unit that is heated to a temperature, which enables a thermal fixing process (hereinafter, a thermal process enabled temperature).
When the fixing unit is always heated to the thermal process enabled temperature, an image formation such as a copying process can be always conducted. However, the heating of the fixing unit consumes a large amount of power. This is not preferable for a user who wishes to suppress power consumption.
JP-A-2002-305614 discloses once storing an image data in a memory without outputting it, when a facsimile is received in a power save mode in which a fixing unit is set to a low temperature. The facsimile is output later at the time of other image formation such as a copy output. This reduces the number of heating the fixing unit. The power consumption is suppressed.
However, in case of a copying process, even when a user intends to promptly complete the copying process, heating of the fixing unit starts after printing is instructed by operating a copy button. The user must wait until the fixing unit is heated to a thermal process enabled temperature. It fails to satisfy a user's request for prompt copying process.
Aspects of the invention provide an image forming apparatus in which, in response to a user's request, power consumption can be suppressed, or the copy time can be shortened.